joccee

Im using fe calc to find a good setup for my micro iceberg.
the only thing I havn't decided yet is if I should use 2s or 3s lipos. but when I use fe calc to see how many amps I will be pulling with lipos I get a 20A difference compared to the same volts on regular gp cells. Is this true in real life to?? or have I done something wrong when I added the lipos to fe calc??

here is the setup
Feigao 380 8S (4934kv)
H-wing 60A esc
Graupner prop 1.4x26
E-power lipos 2x 1700mah

If fe calc is right then if I use 9(11.25v) gp1100mah cells it will draw 45A
but with 3s2p 1700mAh lipos it will draw 70A

hope someone can help me with this...

Got RPM

You have to realize that FECalc is not an absolutely accurate program. When it was first developed - when we ran brushed motors and nickel cells - it was quite close in its predictions. With modern BL motors and LiPo cells the resultsa re less accurate than they used to be....but they are still useful to find an approximate starting point. In your case, you will see a lot more amperage from the LiPos versus the nickel cells. This is because the LiPo cells have much lower internal resistance than the nickels do, and they will give up more power more rapidly. This means more speed with the same voltage. In a test I performed, I got over 30% more amps drawn with 4S LiPos than with I did with 12xIB3600 nickels - everything else was the same.

Bottom line - yes, you will see a higher amp draw changing to LiPos. Will it be 35 amps? Maybe, maybe not.


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joccee

thanks for the help guess I'll run 2s pack then.